The starter circuit shown in the figure was found in an old European documentation. The circuit makes use of an SCR which is still common and the diac can be of any type.
This stage of low power audio amplification was very common in devices powered by the 60's and...
This different circuit was found in a Radio Electronics from August 1965. It works with a voltage of...
This circuit was found in a 1980s documentation from the manufacturer of the integrated. The...